Method of constructing caissons



Filed Aug. 2. 1926 ddulf, @man d C. L. POWELL METHOD OF CONSTRUCTINGCAISSONS Jan. 3, 1928.

nas

Patented Jan. 3, 1928.

UNIT-ED STATESl PATENT OFFICE.

CHARLES LESLIE POWELL, 0F CHICAGO, ILLINOIS, ASSIGNOR 0F ONE-HALF T0OWEN YER-KES, OF CHICAGO, ILLINOIS.

METHOD OF VCONSTIRIJTITING CAISSONS.

Application filed August 2, 1926. Serial No. 126,377.

My invention relates to the construction and formation of caissons,abutments, piles and the like and particularly to such as are formedfrom concrete or other plastic compounds.

In the construction of caissons, etc., 1t has been the usual practice todig orf sink holes in the ground and then lill with concrete. Thismethod is not only very 1aborious but is very expensive and slow in thatthe dirt must all.be dug and taken' from the hole manually. I am awarethat many other methods' for removing the dirt have been experimentedwith and several patents have been granted on methods and apparatus foraccomplishing this purpose but none of these have ever come into suchgeneral and practical use as to obsolete the hole digging methods. Theterm caisson has come to be known in construction work as meaning theconcrete pillar or foundation post formed in the earth and may extendpartly through Water, rock, etc. In the present day construction ofcaissons the forms or, as I shall refer to them, the casings when placedin the holes into which the concrete or other plastic compound ispoured, are left in position surrounding the concrete. This is verycostly and from the standpoint of strength is usually unnecessary.

In my improved method of constructing caissons and the like I firstemploy the well known method used in drilling oil vand gas wells, i. e,drilling into the ground With a tool of the required diameter, so as, toloosen the earth in the path of the drill and supplying the end of thedrill with a copious amount of Water which mixes with the loosened earthto form soft mud. This drilling passes through occasional rock, shale,etc., and extends downward to ybed rock. By this method any Water orquicksand encountered-is quickly sealed by the mud which is forced backinto the sandy formation or yWater so as to Wall up Vthe same, whichsupports and prevents the leakage thereof into the drilled area, all ofwhich is very advantageous and is accomplished by the employment of therotary drill process utilized for breaking up the earthy ma-` terial andwhich is not accomplished by thel old oil Well boring method orpresentcaisson digging method.

In some instancesthe drilling tool is. now removed and a casingsubstantially the same diameter as the drilled tool is now insertedthrough the mud With its lower end resting on the bed rock. In otherinstances the cutting tool Will be left in position until the casing isinserted through the mud. I then remove the soft mud from the interiorof the casing,l and the periphery of tl1e-cas ing will be insubstantially close proximity to the undrilled earth which defines'thecircumferential line of Cutting of the drilling tool. This operationof drawing the. mild from the inside of the casing may be acplasticcompound With the Walls ofv the hole is greatly assisted by'lintermittently tamping the material during the -illing operation. Afterthe casing has been entirely removed We have a solid body of concrete.'

or other material firmly embedded in the uncut Walls of earth and Wheredesired one in which there is no surrounding casing.

W'ith this method of constructing caissons it has been found caissonsrequiring one Week to ten ldays to build by the present day methods canbe completed in from six to eight hours. Another very important featureand one of the principal objects of this invention is the elimination offrequent trouble caused by the crumbling and the caving of the eartharound the hole. In my improved method the uncut side walls of the holewill be supported by the soft mud within the same and before this mud isWith-1" drawn the casing is inserted which provides adequate support forthe side Walls'of un? cut earth.

Other objects and advantages of my im- B'oved method/of constructingcaissons will apparent from the following descriptlon when considered inconnection with the ac- F1 and drilling tool removed, the ottom of thehole filled with concrete and the casing drawn u to about the line offill;

Fig. 4 1s a like view showing a permanent inner casing inserted withinthe sunk casing;

Fig. 5 is an enlarged cross sectional view taken on the line 5-5 of Fig.4;

Fig. 6 is a like view showing the perma nent inner casing formed ofcorrugated metal;

Fi 7 is an enlarged vertical section on the lme 7-7 lof Fig. 2 showingthe manner in which the sections of casing are joined together;

Fig. 8 is a top plan view showing the manner in which the caissons aresometimes connected in tandem; and

Fig. 9 is a like view showing four of the caissons constructed in thesame manner.

In the drawing like symbols of reference indicate like parts.

Having briefly described the method practiced in constructin my improvedcaisson, I will now refer to t e drawing and describe the apparatusemployed in carrying out the metho y A latform 13 is constructed on thegroun with its center at the osition where the caisson is to be located.forniy is constructed a derrick 14 which is provided with the usualblock and tackle devices 16. On the platform or derrick floor 13, Ilocate a standard rotary machine 17 which is provided with a geared rack18 driven by the beveled gear 19 mounted on the shaft 21 which extendsto and is driven by any suitable source of power. vLet us assume thatthe drilling tool 22, above which are located the cutting blades 23. andal1 mounted on the sectional stem 24, to be resting upon the ground atthe Point which I y have indicated by the numeral 26. The stem 24extends through the rotary machine 17 and is rotated from the shaft 21with the said machine and this machine while gri ping the said shaft torotate the same wlll permit longitudinal movement thereofy as the samedrills and cuts its way into the earth. To prevent the tools fromdrilling too rapidly a cable 2Tiis attached to the headpiece 28 of thestem and said cable extends to and is paid out from the drum of anordinary hoist (not shown). After the tools have drilled themselves ashort distance inpon this p'latto the earth loosening the soil aroundvthe same the rotary machine 17 'is sto pcd, the

v other section of stem whereupon the rotary machine 17 is again lacedin operation. This operation of adding sections to the stem 24 willcontinue until the cutting tools 23 have reached and cut a shortdistance into the bed rock, which I have indicated by the numeral 31.During all-the time the drilling tool 22 and cutting tools 23 have beenloosening the earth they have been supplied with a constant stream ofwater entering the interior of the stem 24 from the flexible pipe 32 sothat the loosenedk earth mixing therewith has been changed to mud ofVery thin consistency.

At this point in the operation I may withdraw the tools 22 and 24 byagain operating the rotary machine 17 and placing tension on the cable27, stopping the machine after the tools have been raised a shortdistance, disconnect-ing one of the sections of the stem, lowering thehead piece 28 connecting same with the end of the next section of stemand then again operating the rotary machine and continuing to disconnectsections as'the tools are withdrawn through the mud.

In other instances I may prefer to leave thev tools at the bottom of theloosened material for thetime being.

In either event I now open the jaws (not shown) of the -rotary machine17 so that they will accommodate a section of the casing 33. This casingis then rotated by the machine 17 and as it is substantially of the samediameter as the overall dimension of the cutting tools 23, it will berotated through the `mud and with its outer surface in close proximityto the uncut earth around the mud. This casing 33 is formed in sectionsand the sections are joined together by the threaded portion 34 on thelower end of the upper section meshing with the threaded portion 36 onthe upper end of the lower section so that the entire casing willpresent a smooth and finished appearance and with no lugs, bolts, orother impedimenta to resist the passage of the casing through the mud.As the casing is rotated until it gradually rests upon the bed rock thesoft mud will entirely fill the interior thereof and the next operationis the removal of all mud therefrom. This may be accomplished by usingan ordinary drillers hailing tool or suction may be applied thereto inany suitable manner. Ifthe drilling ltool 22 and cutting tools 23 havenot been formerly removed, a man is now lowered through the and the stemdisconnected, section by section, as previously described. In such case,where the tools are left in the hole, and where they are removed by theforegoing method, the earth around the hole is of such a crumblingnature that it is advisable to have the casing closely follow thecuttingv members in order to hold up the uncut walls around the mud.

. All the mud having been removed from lthe interior of the casing 33,concrete or At intervals throughout the filling ofthe hole with theconcrete the pouring thereof is stopped and the concrete already m thehole is tamped by any suitable means, such as a Weight having a cablepassing over the block and tackle 16 and allowed to drop onto the top ofthe ll, and this tamping action Will force the soft, pliable concreteIfirmly against the uncut earthen walls surrounding the hole. Thisfilling and tamping will continue, and the sections of the casing willbe removed as they emerge from the ground until the entire hole has beenfilled with the concrete mixture firmly tamped into the hole and with noother support than the 4uncut wall of' earth surrounding the same.

The casing 33 is preferably formed of steel or cast-iron, and its Wallsare in most casesabout 1% to 1/2 thick, so that aseotion of the same isof sufficient weight to readily sink through the mud when the same isrotated by the machine 17 Without any additional pressure being placedon the top thereof. The tools 22 and 23 are also of sufficient weight tocut their way through the earth and any rock which may be encounteredWithout applying any pressure thereto.

In some instances, and particularly where specifications require, apermanent `metal casing is provided around the concrete caisson, andthis may be provided for by leaving the casing 33 in the position shownin Figs. 1 and 2 and filling the same with concrete, as described, or athin metal casing 38 about 11g thick having its ends overlapped, asshown at 39, in Fig. 5, may be inserted Within the casing 33 and whenthe concrete is poured therein and the casing 33 withdrawn, the weightof the concrete assist- 'ed by the tamping thereonv will expand the thinmetal casing 38 so that it will beforced firmly against the material 37comprising the `walls of the hold. Inl some cases I may use the form ofinner casing 41 shown in Fig. 6, said casing being formed of corrugatedmetal so that when the concrete is poured therein and the outer casing33 Withdrawn from around the same and the concrete tamped, as aboveexplained, the points of the corrugations 42 will be driven'into thewalls of the earth 37 so as to provide great resistance against crushingstrains applied to the top of the caisson. In this connection it may benoted that the adherence of the caisson to the. earth surrounding thesame, or the pressure of the earth around the caisson is so great thateven with the bedrock support removed from the lower end thereof atremendous upper pressure on the caisson is required to move itdownwardly into the earth or to crush the same. This particular featureplays a lvery important part in the construction of caissons, and withvmy improved method of construction none of the essential featuresexisting in caissons formed after the general practice of today has beenimpaired.

Bearing in mind the pressure of the earth around the caissoncontributing largely to its support, in some instances it may beadvisable to sink caissons in tandem form, as shown in Fig. 8, or evenin quadruple form, as shown in Fig. 9. By this method of constructionthe individual caissons A. have the pressure of the earth around theentire circumference of the same so that for a much less quantity ofconcrete a greater and stronger multiple caisson can be constructed. Ifdesired, these caissons may be topped by a square or round portion ofcrown 43 unit.- ing them together.

In many cases and particularly where the caissons are to he placed inhard earth or clay, it ma be desirable to first drill a hole with therillin tool 22 only, attached to the stem 24, and 1n some caseseven asmaller drill might be first used, and a larger drill subsequentlyconnected with the stem, and the hole redrilled. This drilling would beWithout the cutting tools 23 which ream the hole to the proper diameter.In such cases after the drilling operation has been completed, thecutting tools or reamers 23, would be connected-With the stem, and thedrilling tool 22 either left in position or removed if desired. It mightalso be stated in this con-v nection that in some instances even theouter diameter of the cutting tools 23 would on the first reaming cut besmaller than the re quired diameter of the finished hole, in which caseafter making the first out, new cutting tools 23 of the requireddiameter would be attached to the stem 24 and the earth, rock, etc., cutto the required diameter of the finished hole. While I have in myforegoing description described the hole as being drilled and cut in oneoperation, it will be apparent that so long as I arrive at the finishedresult of a hole cut to the required diameter and filled with soft mud,various methods of cutting and drilling the same may be employed.

It will, of course, be apparent from the foregoing description thatcaissons of'any required diameter may be constructed by this method, andon account of its facility, a great amount of time will be saved in theconstruction of foundations for buildings and the like over thepresent-day methods. In practice this method has been found veryefiicient, and the derrick 14 and rotary machine 17 mounted on theplatform 13 may be moved from spot to spot as the work of constructingthe required number of caissons advances.

lVhile I have shown and described a preferred embodiment ot' myinvention, i/t will be understood that I do not limit myself to thedevices shown and described herein for carrying out my improved method,nor do I limit myself to each and every of the steps described inputting the same into effect. Having in mind the variations which may`be practiced in connection with the method and the different kinds ofapparatus which may be. used in carrying out the same, I claim all suchmodifications and combinations of my improved method as properly f'allwithin the spirit and scope of the appended claims,

I claim:

1. The herein described method of constructing caissons and the likecomprising ing, and drawing the casing from the hole gradually as theconcrete fills the hole.

2. The herein described method of constructing caissons and the likecomprising the steps of first drilling to bed rock while mixing theloosened earth with water to form soft mud, ythen inserting a casingthrough said mud to the bedrock, then removing thc mud from Within thecasing, and then filling the resulting hole with plastic compound whilegradually drawing the casing from said resulting hole.

3. The herein described method of constructing caissons and the likecomprising the steps of first drilling to bedrock while mixing theloosened earth with water to form soft mud, then inserting a casingthrough said mud, said casing being of substantially the same diameteras the drill, then removing the mud from within the cas` ing, thenremoving the drill, and then filling the resulting hole with plasticcompound while gradually drawing the casing from said resulting hole. I

structing caissons and the like comprising the steps of first drillingto bedrock while supplyin the drill with sufficient water which, w enmixed' with the loosened earth, forms soft mud, then inserting a casingthrough said mud to the bedrock, then removing the mud from within thecasing, then filling the resulting hole by pouring plastic compound intothe casing, drawing the casing gradually from the hole as the concretefills the same, and intermittently tamping the concrete so as to forceit into {iriln contact with the ground around the 6. vThe hereindescribed method of constructing caissons and the like comprising thesteps of first loosening the earth down to bed-rock and introducingsufiicient water to form soft mud, then inserting a casing through lthemud to the bedrock, then removing the mud from within the casing, theninserting an expansible casing within said first casing, then fillingsaid expansible casing with plastic compound while drawing said firstcasing from the resulting hole so as to permit the expansion of saidexpansible casing into contact with the ground around the hole.

7. 'lfhe herein described method of con--v structing caissons and thelike comprising from within said casing, then inserting ank expansiblecorrugated casing within said first casing, then filling said corrugatedcasing with plastic compound while drawing said first casing from theresulting hole so as to permit the expansion of said corrugated casinginto contact with the ground around the hole.

8. The herein described method of con'- structing caissons and the likecomprising the steps of' first loosening the earth and introducingsufficient water to form soft mud, then inserting a casing through themud to the bedrock, then removing the mud from within said casing, theninserting an expansible corrugated casing within said first casing, thenfilling said corrugated casing with plastic compound while drawing saidfirst casing from the resulting hole, tamping said plastic materialintermittently while filling said corrugated casing so as to expand thesame and drive the corrugations into the ground around the hole.

9. The method of constructing caissons which consists in looseningtheearth and supplying the same with water to form--a soft mud that isallowed to remain in the loosened area after the loosening operationceases, inserting a sectional casing through said mud, removing the saidmud from the interior of said casing, and finally filling concrete intothe interior of said casing and progressively withdrawing anddisconnect-- ing sections of said casing as the filling proceeds.

10. The method of constructing caissons which consists in drilling intothe ground with a tool of progressive diameters and supplying said toolwith a copious amount of water to form a mud that is allowed to remainin situ, inserting a sectional casing through the soft mud formed by themixing of said water with the earthy material loosened bysaid tool,removing said mud from the interior of said casing, and finally fillingconcrete into the interior of said casing and progressively withdrawingand disconnecting sections of said casing as the filling proceeds.

11. A method of sinking caissons in the earth, comprising loosenin andbreaking up the earthy material' which is to be displaced to make roomfor the caisson, supplying liquid to the broken up material while it'isstill in the drilled area to form a fluid mass in said area which exertspressure against the uncut sides thereof sufficient to resist caving inand the entrance of water and quicksand to the loosened area, sinking acasing in said area while the fluid -mass is still therein, withdrawingthe fluid mass from within the casing, and supplying the caissonmaterial to the resulting hole through said casing.

12. A method of sinking caissons in they earth, com rising loosenin andbreaking up the eart y material which is to be displaced to make roomfor the caisson, supplying liquid to the broken up material while it isstill in the drilled area to form a fluid mass in said area which exertspressure against the uncut sides thereof sufficient to resist caving inand the entrance of water and quicksand to the loosened area, sinking acasing in said area while the fiuid mass is still therein, withdrawingthe fluid mass from within the casing, supplying the caisson material tothe resulting hole through said casing, and withdrawing the casing fromthe hole, leaving the caisson material in place in the hole.

13. The herein described method of constructing caissons and the like,which comprises' the steps of first loosening the earth withintroduction of water to form a soft mud, thereupon inserting an openended casin down into the soft mud, removing the mud groin within thecasing, placing a plastic setting material into said casing, andremoving the casing before said plastic material has set.

14. The method of preventing the caving in of openings being made in theearth, which comprises loosening the earth with the addition of water soas to form mud that remains in the loosened area, and thereuponinserting an open ended casing into said mud.

15. The method of constructing caissons and the like which comprisesdrilling into kthe earth with the addition of water to form a mud thatremains in the loosened area, allowing a casing open at both ends tosink downwardly into and through said mud by Aits own weight until itstrikes and rests against the non-loosened undrilled earth, removing themud from within said casing, placing a plastic 'material capable ofsetting into said casing, withdrawing the said casing prior to thesetting of the said plastic material, and allowing said material to setand harden.

In witness whereof, I have hereunto subscribed my name.

CHARLES LESLIE POWELL.

